Murray holds a slight edge over Federer in their FedEx ATP Head2Head series, 11-10, though the Swiss won their most recent meeting in the Australian Open quarter-finals. They have split their two encounters in Cincinnati.

"I played a really good match against him in Australia," Federer said in a post-match interview with ESPN. "I know he probably wasn't at 100 per cent but I personally played a good match. That's how I have to come out tomorrow.

"I'm happy for him that he's playing [well] again. He was close against Tsonga last week... could have had a run there. That's why I know the danger of this match tomorrow. I think it was a huge match for him to beat Isner. Those are the kind of matches you need to win to get going again. I know I'm in for a tough one."

Federer, playing Monfils for the first time since a defeat last October in Shanghai, dropped serve to begin his third-round match. He came back, going three for five on his break point chances, to clinch the opening set.

Monfils made a late charge in the second set and continued to put pressure on Federer, earning three chances to break early in the third. He was unable to capitalise, while the World No. 3 went up the decisive break in the eight game and served out the win after one hour and 48 minutes.

"I thought I returned pretty well tonight... much better than I have in my previous matches," he said. "That's really what kept me calm throughout the match. I tried to come forward because the conditions are quite fast here. I think that was a good tactic out here tonight."

The 33-year-old Swiss became the first player to reach 300 match wins at the ATP World Tour Masters 1000 level on Wednesday with his three-sets win over Vasek Pospisil. He finished runner-up to Jo-Wilfried Tsonga last week in Toronto.

"I have a different eagerness today," said Federer. "I was a bit more erratic when I was younger: good day, bad day, medium day, I was a bit all over the place. I think I've gotten my act together over the years. I think I'm in a good spell right now. I have a lot of tennis in my legs right now. I go day by day. I have a great team behind me and a wonderful family. I'm very much at peace with how I need to play."